Oracle Scheduling Using the Windows Job Schedulers Oracle Tips by Burleson Consulting

Using the Windows Job Schedulers

AT.EXE

The AT command can be used to schedule commands and programs on Windows NT, Windows 2000, Windows XP and Windows 2003.  For the command to work, the scheduler service must be running.  On Windows 2000, this can be done using the services dialog (Start --> Programs --> Administrative Tools --> Services) or from the command line using the net command:

net stop "Task Scheduler"
net start "Task Scheduler"

The at /? command produces the following:

AT [\\computername] [ [id] [/DELETE] | /DELETE [/YES]]
AT [\\computername] time [/INTERACTIVE]
    [ /EVERY:date[,...] | /NEXT:date[,...]] "command"

\\computername     Specifies a remote computer. Commands are scheduled on the
                   local computer if this parameter is omitted.

id                 Is an identification number assigned to a scheduled
                   command.

/delete            Cancels a scheduled command. If id is omitted, all the
                   scheduled commands on the computer are canceled.

/yes               Used with cancel all jobs command when no further
                   confirmation is desired.

time               Specifies the time when command is to run.

/interactive       Allows the job to interact with the desktop of the user
                   who is logged on at the time the job runs.

/every:date[,...]  Runs the command on each specified day(s) of the week or
                   month. If date is omitted, the current day of the month
                   is assumed.

/next:date[,...]   Runs the specified command on the next occurrence of the
                   day (for example, next Thursday).  If date is omitted, the
                   current day of the month is assumed.

"command"          Is the Windows NT command, or batch program to be run.

A couple of simple examples of its use include:

C:> at 21:00 /every:m,t,th,f "c:\jobs\MyJob.bat"
Added a new job with job ID = 1

C:> at 6:00 /next:20 "c:\jobs\MyJob.bat"
Added a new job with job ID = 2

The first example schedules a job which runs the c:\jobs\MyJob.bat script at 9:00 p.m. on Mondays, Tuesdays, Thursdays and Fridays.  The second example schedules a job that runs the script at 6:00 a.m. on the next 20th of the month.

User ID = reader, Password = program

The current list of jobs can be displayed by issuing the at command with no parameters:

C:\>at
Status ID   Day                     Time          Command Line
--------------------------------------------------------------------
        1   Each M T Th F           21:00 PM      c:\jobs\MyJob.bat
        2   Next 20                 06:00 AM      c:\jobs\MyJob.bat
 

C:\>

Jobs can be deleted using the /delete option:

C:\>at 1 /delete

C:\>at 2 /delete

C:\>at

There are no entries in the list.

C:\>

The AT scheduler has been at the heart of Windows scheduling for some years, but recent Windows versions have introduced simpler and more flexible alternatives, which will be covered in the following section.

Scheduled Tasks Wizard

In Windows 2000, Windows XP, and Windows 2003 there is a GUI tool called the Scheduled Tasks Wizard, which is far more convenient than the AT command.  It is available from the Control Panel or from the task bar (Start --> Programs --> Accessories --> System Tools --> Scheduled Tasks).  The resulting dialog lists the current scheduled tasks and an Add Scheduled Task icon, as seen in Figure 1.1.

Figure 1.1 ? Scheduled Tasks dialog with no scheduled jobs

To schedule a new task, simply double click on the Add Scheduled Task icon, which starts the Scheduled Tasks Wizard as shown in Figure 1.2.

Figure 1.2 ? Scheduled Tasks Wizard

Clicking the Next button produces a list of programs that can be scheduled as shown in Figure 1.3.  If the program or script that is desired is not available in the list, the Browse button allows the user to select alternatives from the file system.

Figure 1.3 ? Scheduled Tasks Wizard:  program list

Once the relevant command or script is selected, clicking the Next button displays a screen that allows a name and basic schedule to be associated with the task as shown in Figure 1.4.

Figure 1.4 ? Scheduled Tasks Wizard:  name and basic schedule

The contents of the next screen vary depending on the type of basic schedule selected.  Figure 1.5 shows the additional schedule information that can be defined for a daily task.

Figure 1.5 ? Scheduled Tasks Wizard: additional scheduling options

The next screen, Figure 1.6, permits authorization credentials for the task to be assigned, allowing the task to run as any valid operating system user.  It is important that tasks run with the correct credentials, as running tasks under privileged accounts can introduce potential security holes. 

Figure 1.6 ? Scheduled Tasks Wizard:  authorization details

Finally, a summary page is displayed, as shown in Figure 1.7, which gives the option of displaying the advanced properties dialog once the job definition is complete.  If this option is left unchecked, clicking the Finish button displays the original scheduled tasks list.

Figure 1.7 ? Scheduled Tasks Wizard:  summary

The newly scheduled task is now displayed in the scheduled tasks dialog as shown in Figure 1.8.

Figure 1.8 ? Scheduled Tasks dialog with newly scheduled job listed

Right clicking on the job and selecting the Properties option from the pop-up menu in Figure 1.9, displays the advanced properties dialog.  This dialog allows the task definition to be modified after it is created.

Figure 1.9 ? Scheduled job properties dialog

The following section will present the SCHTASKS command which provides a more feature rich command line alternative to the AT command.

 

This is an excerpt from the book "Oracle Job Scheduling" by Dr. Tim Hall. You can buy it direct from the publisher for 30%-off and get instant access to the code depot of Oracle job scheduling scripts.